Entero-adherent aggregative Escherichia coli (EAggEC) is now considered to be a new subgroup of diarrheagenic E. coli which cause persistent diarrhea in children. Epidemiological studies in India and Chile indicate that this pathogen may have as much impact on public health, as the other enterotoxigenic strains. In India, Bhan and Kumar have observed 35-50% of diarrheal deaths are caused by persistent diarrhea reflecting that this putative pathogen may be the initiating cause of over a third of diarrheal episodes in young children. It is proposed at EAggEC strains isolated from children with persistent diarrhea will be characterized with regard to their serotypes, plasmid profile, hemagglutination patterns, antibiotic sensitivity, enzyme profile and fimbrial and other surface structures. The possibility of toxin production by EAggEC will be checked in different cell lines. Pathogen specific gene probe will be developed which will be used for diagnostic purposes. To understand the molecular mechanism of pathogenesis the genes responsible for the virulence and adherence properties will be identified and characterized. These investigations may lead eventually to the development of vaccine.